A quantization noise reduction method and a quantization noise reduction method which are generated during image data decoding processing,

摘要

An apparatus for decoding coded image data divided into a plurality of blocks so as to generate decoded image data by applying an inverse orthogonal transform to each block among a plurality of blocks includes a block quantizer And a quantization information detection unit 5 for detecting the picture width value information. The apparatus also includes a variable gain low pass filter (7) for reducing a high frequency component of the decoded image data having a frequency higher than a predetermined frequency, based on the block quantization width value information,